Been saying Ala Mihgo was 4.0 for ages now.
It's literally the only thing we have going for us in the story along the same style Ishgard was hinted at before 3.0. Moreover, Garleans have more or less rallied from their loss and are encroaching on us again. We'll probably just retake Ala Mihgo and secure a foothold for 5.0 INTO GARLEMALD
Ala Mihgo is the most likely place for 4.0 but given what has happened with the heavensward expansion I expect Ala Mihgo would just be the start, there is likely going to be some other location of high importance that will be set in motion that won't be related directly with garlemald, if we don't have content that takes us to the moon, I fully expect that will be an actual place we visit in 4.0 since its also pushing us to that locale and Yoshida mentioned wanting to go there right before 3.0 released. Remember Yoshida mentioned from the start that 4.0 would not require the patch story enhancements to participate in the content (3.X he mentioned) but that does not mean it won't require 3.0, the originaly story, since the new expansion will likely have majority content set to lvl 60. The only content from 3.0 story that we aren't tackling and likely finishing in the 3.X series is the Moon storyline (Warrior of Darkness), and the advancement of the Garlean forces with the new emperor at the front of it all. Some elements of the Warrior of darkness storyline is showing up in 3.X but no more then teases.
The other things that point to that is of course all the Ul'Dah storyline (Nanamo red herring) from 3.0 and the new platoon content coming in 3.4 where we use our grand company to train a squad/mini army, and a direct war with Ala Mihgo would be obviously the best way to add that content into the game (Train for the eventual conflict). Having said that I am curious to see if that is the route of the new expansion what new areas they will be adding. I feel like a war with Garlean Forces would not happen on just one front, I am hoping they will take the opportunity to add some additional territory back into some of the old locales (lost or completely new) like West Shroud, Northern Highlands of Coerthas and the eastern low lands, or new territory between the Crystal tower and the western shroud (the missing portion of lower Mor Dhona) or Pagalthan, or the Volcano/northern part of Vylbrand, but maybe they will save that for a more focused expansion down the line.
No. Already kicked his ass more than enough times leveling up in the Aery.
Please look forward to Aery HM is patch 4.3.
Think it is fairly safe to say the whole dragon song conflict will end in the 3.X patch line. My guess is the final story arc will be a dedicated trial between Nidhogg and the Players, he has changed after all now that he has both his natural eyes as well as Dragoon capabilities, should make for a fairly different fight
(And yes I am tired of his fight too since all but two of my combat jobs are lvl 57+)